The optical transmission characteristics of optical fibers can be seriously degraded when a fiber is bent or kinked in too small a radius. Also, since optical fibers are relatively fragile structures which can break if they are bent below a certain radius or if they are twisted too sharply, fiber optic cables are designed to have a number of protective layers and elements formed around the optical fibers to prevent any damage from occurring to the fibers and to control, at least to some extent, the degree of bending. In many fiber optic cables, these protective layers and elements include a core tube for encasing the optical fibers, an armor sheath formed of a metallic material which is wrapped around the core tube, and an outer jacket formed of a medium or high density polyethylene.
When an optical fiber is to be spliced to, for instance, another optical fiber, the outer protective layers of the cables must be removed to expose the ends of the optical fibers. The ends of the fibers are then inserted within a splice which holds the ends of the fibers in alignment with, and abutting, each other. As is typical in the industry, an optical fiber splice closure receives the fiber optic cables, protects the exposed optical fibers, and holds the optical splices. The optical fiber is separated from the core tube within a splice tray in the closure and an insert within the splice tray holds the actual splice. Because each splice tray can only hold a limited number of splices, each optical closure typically contains a number of splice trays which are usually stacked on top of each other in order to hold all of the necessary splices.
An installer or lineman often needs to reenter individual splice trays in the stack to perform additional work, such as to perform additional splices or repair existing splices. The installer or lineman, however, may encounter some difficulty in accessing a splice tray other than the top tray since all of the splice trays above the desired splice tray must be moved to another location or otherwise out of the way, which may be difficult given the often limited amount of space in the closures and the constraints imposed by short fiber lengths.
This difficulty has, to some extent, been overcome with some splice trays which are currently being manufactured with leaf members having holes therein at the two bottom rear corners of the trays and hinge pins at the two top rear corners of the trays. When these splice trays are stacked on top of each other, the hinge pins on a lower splice tray protrude into the holes formed in the leaf members of an upper splice tray. With such an arrangement, the installer or lineman can more readily access a desired splice tray by simply pivoting the upper splice trays away from the desired splice tray. See, for example, the splice trays shown in U.S. Pat. No. 5,519,804 of Burek et al., filed Jun. 22, 1994. Unfortunately, most of the earlier manufactured splice trays and some of the presently manufactured trays, such as the Keptel LL-2400.RTM. splice tray, do not have these hinge pins and leafs. A need therefore exists for a device for providing a hinging capability to these pre-existing splice trays so that lineman or installers can more readily access all of the splice trays in an optical closure.